<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>计数器</title>
    <script src="https://unpkg.com/vue@next" ></script>
</head>
<body>
    <div id="app"></div>
</body>

<script>
    Vue.createApp({   // 创建一个VUE实例
        data() {
            return {
                counter: 1
            }
        },
        mounted() {
            setInterval(()=>{
                this.counter += 1;
            }, 1000)
        },
        template: '<div>{{counter}}</div>'
    }).mount("#app")
</script>
</html>